MOSCOW/ SIMFEROPOL The Kremlin warned Tuesday that Ukraine’s declaration of martial law over Russia’s seizure of three Ukrainian ships might trigger a flare-up in hostilities in eastern Ukraine, while Kiev blamed Russia for parading captured Ukrainian seamen on TV.

The Ukrainian parliament on Monday adopted a motion by the president to impose martial law for 30 days after Sunday’s clash between the two rivals in the Kerch Strait, which links the Black Sea and the Sea of Azov. That is something Ukraine avoided doing even when Russia annexed its nearby Crimean peninsula in 2014, or sent in clandestine troops and weapons to insurgents in wartorn eastern Ukraine.

On Sunday near Crimea, Russian border guards rammed into and opened fire on three Ukrainian navy vessels traveling from the Black Sea toward a Ukrainian port. The Russians seized the ships and their crews.

It raised fears of a wider escalation — in a conflict that has killed more than 10,000 people since 2014 — and prompted international calls for restraint.

A court in Russian-annexed Crimea on Tuesday ordered three Ukrainian sailors to be held in custody for two months after the weekend confrontation at sea with Russian border guards. “For now, the court has ordered three people held until January 25” on accusations of crossing into Russian territory illegally, Crimea’s rights ombudswoman Lyudmila Lubina said.

Several others of the 24 Ukrainian sailors held by Russia were expected to appear in court later Tuesday.

Kremlin claims ‘provocation’

The Kremlin reacted strongly to Ukraine’s declaration of martial law, with Dmitry Peskov, Russian President Vladimir Putin’s spokesman, telling reporters Tuesday that it might trigger a flare-up in hostilities in eastern Ukraine. The martial law takes effect Wednesday in several parts of Ukraine, including areas bordering territory held by separatists.

Russian intelligence agency FSB claimed the ships had Ukrainian SBU intelligence agents onboard with a mission to mount “provocation” in the Kerch Strait. The SBU on Tuesday confirmed the presence of its officers on the ships but said they were only carrying out counterintelligence for the Ukrainian navy.